Common camera imaging systems generally use a lens system, including one or more lenses, to focus light into an image which is converted into electrical signals by an electrical device. One type of electrical device which is commonly used is an array of Charged Coupled Devices (CCDs). This device measures the intensity of the focused light at selected spatial positions. The selected spatial positions generally define an orthogonal matrix structure made up a of a predetermined number of rows and columns.
During the conversion from a light image to electrical signals, the image may be distorted due to the imperfections in the lens system and in the CCD arrays. These distortions may be inherent in the system, for example, geometric distortions or chromatic aberrations in the lens system, or they may be caused by errors in component manufacture or assembly, for example, misregistration due to the misalignment of the CCD arrays. The chromatic aberrations caused by lenses act to positively or negatively magnify images while the misalignment of the CCD arrays acts to laterally or vertically shift images.
Lateral chromatic aberrations occur because light rays of different frequencies are magnified differently by a lens. Thus, for a color picture which is commonly separated into the tripartite system of Red, Green, and Blue (R, G, and B) images, the three color images have different levels of magnification after being processed by the same lens.
Misregistration occurs in camera systems because the separate CCD arrays are not consistently aligned. Commonly, a white light image is separated into different monochrome light images, e.g., red (R), green (G) & blue (B) images and then sampled by separate CCD arrays. If the CCD arrays are not properly aligned, the different light images will be sampled at different spatial positions. This misregistration of the sampled images causes color edges in the combined images to appear at different positions.
The current solution to eliminate the distortions caused by lenses and the misregistration by CCD arrays is to make lenses with stringent design criteria and mount CCD arrays with stringent tolerances. These solutions, however, also lead to expensive camera systems.